PL/pgSQL is the default procedural language of PostgreSQL. PL/pgSQL allows you to:
- Create reusable database functions and stored procedures with complex business logic, including if-else and loops.
- Automate repetitive PostgreSQL database tasks.
PL/pgSQL in PostgreSQL shares a similar syntax with PL/SQL in Oracle Database, making it easier for Oracle Database developers to transit to PostgreSQL.
PL/pgSQL key features #
PL/pgSQL has the following key features:
- SQL integration: PL/pgSQL can execute SQL statements seamlessly within its code.
- Block structure: PL/pgSQL offers a block structure that organizes the code into blocks, making it easier to develop.
- Control structures: PL/pgSQL support conditionals and loops.
- Error handling: PL/pgSQL provides a robust error-handling mechanism.
- Dynamic SQL: PL/pgSQL can construct SQL queries flexibly and execute them dynamically.
Advantages of PL/pgSQL #
PL/pgSQL makes PostgreSQL more powerful by:
- Boosting PostgreSQL performance and reducing latency by avoiding multiple client-server round trips.
- Centralizing the business logic at the database layer for consistency.
- Bringing an imperative programming model to the database programming.
Section 1. Getting Started with PL/pgSQL #
In this section, you’ll start with the PL/pgSQL procedure language:
- PL/pgSQL blocks – Learn how to organize the PL/pgSQL code into blocks.
- Variables – Show you how to declare variables in PL/pgSQL and help you understand variable scopes.
- Select Into – Select data from a table and assign it to variables.
Section 2. User-defined functions & procedures #
In this section, you’ll learn how to define functions and stored procedures using PL/pgSQL.
- PL/pgSQL functions – Learn how to create a user-defined function using PL/pgSQL.
- PL/pgSQL procedures – Show how to define procedures using PL/pgSQL.
Section 3. Control Structures #
In this section, you’ll learn the basic control structure, including if, case, and loop statements.
- IF statement – Add conditional logic to the PL/pgSQL block using the if-else statements.
- CASE statement – Learn how to use the CASE statement to execute code based on one or more conditions.
- LOOP statement – Perform a code block repeatedly using the loop statement.
- WHILE LOOP statement – Create a pretest loop using the while loop statement.
- FOR LOOP statement – Use for loop to iterate over rows of a result set and process each individually.
- EXIT – Learn how to terminate a loop prematurely.
- CONTINUE – Learn how to use the continue statement to skip the current iteration and immediately start the next one.
Section 4. Exceptions #
In this section, you’ll learn how to handle exceptions, raise errors, and use assertions.
- Handling exceptions – Catch and handle exceptions using the EXCEPTION block.
- Raising exceptions – Learn how to raise exceptions using the RAISE statement.
- Assert – Add debugging checks to the program using the assert statement.
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